I'm trying to extend the nikkei back in time by "linking" the cash contract onto the more recent NK futures data but I'm not having much luck. Is trying to link cash and futures data a bit of a faux pas ???

Hi Jas,
NQ and ND3 cash are currently hard linked, meaning they both share the same cash contract data, starting in 19851001, and are both currently being updated. You should be able to see a cash contract available for NQ. Please let me know if you need any assistance.

Sorry Josh, I meant to say originally that I was trying to link Nikkei SSI_54 to the NK futures contract.

What I am trying to achieve is to extend the Nikkei future back to 1985 using representative data so that I can use it for correlation purposes. The idea was to splice the SSI cash contract onto the beginning of the NK future to get this effect, is it possible ?

Have you linked your simbols for a better test?
Double check that Trading Blox is reading them, because till you save, chart, rewrite, rerfresh and make a prayer, could it be that csi chart is linked, but trading blox is still reading the old file.